IoT Technology Drives Bluetooth® Low Energy Solution Enhancing the "otta" Personal Monitoring Service

Case Study: Bluetooth® Low Energy Solution [Development Story: otta Part 1]

"otta" is currently drawing attention as a new type of monitoring and locator service. In line with the commencement of its commercial operation from the spring of 2017, a new tracking device utilizing a Bluetooth low energy beacon (BLE beacon) also made its debut. The beacon is an example of IoT (Internet of Things) technology. Here we present the story behind the development of this beacon which plays a crucial role in the unique monitoring service.

Case Study Details

Aiming to realize a monitoring and locator service with a terminal that can be easily used by anyone

In spring 2017, the personal monitoring service "otta" began commercial operation in locations, including Minoo City in Osaka Prefecture and Ichikawa City in Chiba Prefecture. It currently is attracting interest because it is based on a unique service concept that distinguishes it from other monitoring and tracking services.

Despite the declining birthrate, the number of cases where children become victims of crime shows an increasing trend. On the other hand, as society ages, the wandering of elderly people is becoming a social problem. To address such issues, services and technology aimed at meeting the needs of socially vulnerable groups such as children or aged persons are increasingly being developed. At this point, various such services are already being offered.

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Figure 1: Image of "otta" monitoring service

The most common type are services that rely on the GPS (Global Positioning Satellite) function in smartphones and similar devices. As these services allow remotely locating a GPS terminal with high accuracy in real time, the number of users is on the rise. However, because most of the services utilize the cellular phone network, they involve communication and usage charges, making them affordable only to a segment of the population. Furthermore, many primary schools and middle schools prohibit their students from bringing cellular phones onto the premises, which makes GPS based services unavailable at the time when they may be needed most, namely on the way to and from school, where children are most likely to suffer involvement in accidents or crimes.

Under such circumstances, "otta" was developed as a service to solve the problem with existing tracking terminals and to realize "a monitoring system that can be easily used by anyone and be brought to school".

A service and terminal that can be easily used by anyone

The technology behind the "otta" system is called Bluetooth low energy beacon (subsequently BLE beacon), which ties in with IoT (Internet of Things) technology. Main function of the device carried by the person being monitored such as a child is BLE beacon transmission only. BLE beacon receivers (detection terminals) mounted for example in schools and at other locations in the community, as well as smartphones running a dedicated "otta" application (watchers) pick up the BLE beacon signal and upload the collected information to a cloud server. Parents or other guardians can check the location history and receive notification that their child has arrived at a specific place such as a school. As the number of users increases, the more complete will the monitoring network become, so that in effect the town and the community as a whole are acting as a fine mesh for protecting their charges.

Because the system does not rely on GPS, the tracking device can be kept small and inexpensive while realizing long battery life and easy operation. Fumikazu Yamamoto, founder and president of otta Inc. that provides the monitoring service, points out that the reception of notifications and location history information is not limited to smartphones, but can also be realized on regular cell phones, which demonstrates that the system is designed to be easily used by anyone.

otta service outline

Figure 2: "otta" service outline

Problems with the terminal that surfaced during practical testing from May 2015

Yamamoto used to be a system engineer, but when he became a father he hit upon the idea of a monitoring service, which eventually led to quitting his former job and founding his own company to pursue the idea in earnest. That was in October 2014, and the company was named "otta". Together with a contracted development company, work began immediately to create a BLE beacon device that would form the basis of the monitoring service. Trial testing started in the Hiroshima area in May 2015.

The BLE beacon device used in this initial phase was shaped somewhat like a macaron (a round meringue confection). In addition to the BLE beacon function, it also incorporated an electronic security buzzer, which was intended to provide an added incentive to carry the terminal when leaving home.

BLE beacon device with integrated security buzzer, manufactured for the trial system

Figure 3: BLE beacon device with integrated security buzzer, manufactured for the trial system

The general results of the trial were favorable, as indicated by comments such as "We appreciated the convenience of being alerted when our child reached a preset goal, such as the school or prep school or a friend's house." However, improvement from various aspects were also identified. The battery used in the terminal was a coin-type CR2354, which could not easily be bought in a supermarket or convenience store. As Yamamoto recalls, "In order to improve the convenience which is supposed to be a major advantage of "otta," we felt that a more easily obtainable battery was needed."

With a view towards easy affordability, keeping manufacturing costs low was another aspect that required attention. Although the terminal used in the trial remained under a given production cost limit, the system concept is based on the premise of BLE beacon devices being distributed for free, and minimizing the cost as much as possible was therefore desirable. However, Yamamoto recalls that he felt it would be quite difficult to further reduce costs. "The terminal used in the trial was built around a general-purpose commercially available BLE module. I thought that if we were to develop a purpose-built BLE module, a cost reduction might be feasible."

Also, to improve battery life as long as possible, the idea of replacing the power-consuming security buzzer with a security whistle was also born during the trial.

Developing an improved beacon device to create a commercially viable system

Having obtained a positive response from the trial, it was decided to work towards commercialization and embark on the development of a BLE beacon device incorporating the improvements identified during the trial. Yamamoto lists the main concept points as follows:

  • Provide a security whistle to replace the security buzzer
  • Adopt a thin long shape resembling a security whistle
  • Develop a custom board rather than using a commercially available module, and achieve further reduction in costs compared to the trial prototype
  • Realize battery life for at least one year (beacon transmission cycle: 1 second)
  • Use a battery type that is easily available (sold in convenience stores)
  • Projected initial order volume: 200,000 units
  • Realize mass production to coincide with commercial service start in February 2017

To enable realization of these concept goals, the company began looking for a partner, but this proved more difficult than expected. "No manufacturer wanted to sell us chip with a volume of 200,000 units. It seemed like buying ready-made BLE modules was our only option" per Yamamoto.

An introduction by a friend leads to development of the ideal beacon device

At this juncture, an acquaintance of Yamamoto's offered a piece of advice in the spring of 2016, "Why don't you consult Renesas Electronics?". As it turned out, that friend had gone to the "Renesas DevCon 2015 OSAKA", a private event hosted by Renesas in February 2016. There he had seen a demonstration of 1-yen coin sized BLE module, which would be perfect for a slender whistle-shaped terminal.

After receiving the contact details of the person in charge at Renesas, Yamamoto immediately went ahead and got in touch. "In the past, I was involved in a job that had to do with the operation of a semiconductor plant, so I knew of Renesas as a chip manufacturer. I thought that approaching a chip manufacturer directly to explore the possibility of a custom-made board was a good idea."

In April 2016, Yamamoto explained the concept of their improved BLE beacon device during the first meeting with Renesas and received an answer right then and there: "Yes, we can do this." He was referred to one of Renesas' partner companies, Tessera Technology Inc. (subsequently "Tessera") engaged in the design, development and manufacture of electronic devices.

Detailed specifications were then worked out together with Tessera engineers and things proceeded smoothly. The specifications were finalized in June 2016, a mere two months after the first meeting, and the prototypes were ready in August of the same year. As a result, a whistle type BLE beacon device designed for the commercial service was unveiled at CEATEC JAPAN held in October 2016.

1-yen coin sized BLE module introduced at

Figure 4: 1-yen coin sized BLE module introduced at "Renesas DevCon 2015 OSAKA"

"We were able to realize the original concept almost completely."

The finished whistle type BLE beacon device "otta.w" is 86 mm long and 10 to 18 mm in diameter. The tip at one end is a whistle shaped from the plastic body. Without relying on battery power, it can produce a loud sound as a means to alert people in the vicinity to a dangerous situation. The same plastic body also houses the BLE beacon and its battery.

Whistle type BLE beacon device otta.w

Figure 5: Whistle type BLE beacon device "otta.w"

The battery is a size N (IEC LR1) which is available at convenience stores. Similar to the terminal used in the trial, the maximum radio range is 100 meters (line of sight). With a beacon transmission interval of 1 second, the battery will not need replacement for at least 1 year. The commercial service utilizing the "otta.w" went into operation in February 2017 as originally scheduled. According to Yamamoto, the results are encouraging, and there have been no battery exhaustion reported so far, more than half a year after the launch.

This type of highly compact BLE beacon device with long battery life was made possible by the RL78/G1D microcontroller chip from Renesas which incorporates a BLE RF transceiver. The outstanding feature of the RL78/G1D is its low power consumption, achieved by utilizing the technology described in the paper "A 6.3mW BLE Transceiver Embedded RX Image-Rejection Filter and TX Harmonic-Suppression Filter Reusing On-Chip Matching Network." This paper was included in the 2015 collection of papers by the ISSCC (International Solid-State Circuits Conference), the foremost global forum in this field. When performing RF transmission which is the most power-intensive state of a beacon device, it consumes a mere 4.3 mA (at 0 dBm). Without the RL78/G1D, achieving a battery life of over a year with a size N battery would have been all but impossible.

RL78/G1D microcontroller chip with BLE RF transceiver

Figure 6: RL78/G1D microcontroller chip with BLE RF transceiver

Another important advantage of the RL78/G1D is the fact that it incorporates the necessary circuitry for antenna connection (balun circuit) as well as a DC-DC converter. Compared to competing products, there are fewer peripheral components which helps in keeping cost low and makes it easier in realizing small dimensions.

Regarding the production costs for "otta.w," Yamamoto says that a reduction of more than one third as compared to the beacon of the trial system was achieved. "Tessera helped us in various ways in our attempt to reduce manufacturing costs. Although there is still room for improvement, we believe that the original concept was largely realized. We are happy with the functionality and design, as well as the final quality."

Why it was possible to unveil a product at CEATEC only half a year after the first meeting

First meetings with Renesas and Tessera in the beginning of April were followed by firming up the specifications, and only half a year later a new terminal was presented at an exhibition in October 2016. Yamamoto points out that the development period was only half that required for the trial system terminal, adding, " we believed from the start that Tessera would be able to keep up a fast pace."

Shintaro Ito from Tessera's Sales Division, Product Planning and Development Section recalls, "Although there was some initial uncertainty as to whether we would be able to manage the short development period, our actual achievement with other projects using the RL78/G1D enabled us to proceed smoothly." For one thing, the 1-yen coin sized BLE module that became the trigger for Yamamoto's encounter with RL78/G1D and Renesas had been developed by the "IoT Subcommittee" formed by Renesas and its partners for working towards future IoT solutions, and Tessera therefore had been involved in its development as well.

As Ito explains, "What's time consuming in development is the software part. Normally, one will have to wait for hardware development before embarking on the software, but in the case of the RL78/G1D, the division between hardware and software was clear-cut, and the two were being developed side-by-side. Furthermore, a full range of software stacks was already available including stacks for functions such as beacon, remaining battery status and OTA (Over The Air) updating which were required for the terminal, so the software development itself proceeded quickly. Without these ready-made stacks, development and mass production would not have been possible in such a short time."

Fumikazu Yamamoto, President of otta Inc.

Figure 7: Fumikazu Yamamoto, President of otta Inc.

Steady growth and new challenges

Since the commercial service began operation in February 2017, the BLE beacon tracking device "otta.w" created jointly by the three companies otta, Tessera and Renesas has been distributed to more than 10,000 elementary school and middle school students. There have been no unforeseen problems and the service runs smoothly. "The number of charged subscriptions for the notification service is steadily growing. Community testing for elementary school students and elderly people has begun in Shibuya Ward from June 2017. We expect the first lot of 200,000 units to run out sometime during 2018." As reflected by these comments, the business is growing steadily.

"The current whistle type is designed for children, but we are also developing a terminal with functions and a shape designed more suited to the elderly. And it goes without saying that we're again working together with Tessera and Renesas on this" per Yamamoto. For otta, Tessera and Renesas, a period of new challenges has already begun.

More Information for Renesas Bluetooth Low Energy Solutions

Easy & Versatile Connectivity

As a solution compatible with Bluetooth Low Energy technology, Renesas offers small modules that can also use microcontroller peripheral functions. It adopted RL78/G1D, the lowest power consumption microcontroller in the industry and is an excellent energy saving item.

In the following material, you can see the overview, evaluation tools, application example for beacon… etc. of “small size/energy saving/Bluetooth Low Energy compatible microcontroller RL78/G1D" introduced in this article.

In Part 2, you will see the discussion between Yamamoto from otta Inc., Ito from Tessera and Renesas representatives about the behind-the-scenes development story of otta.w and future plans of otta personal monitoring service.

otta Part 2: Development of Bluetooth® Low Energy Beacon Device for the "otta" Personal Monitoring Service

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